A projection lens includes a first lens group with a negative refractive power, a second lens group with a negative refractive power, and a third lens group with a positive refractive power, wherein the second lens group is disposed between the first lens group and the third lens group. The first lens group includes an aspheric lens. The second lens group includes a first lens and a second lens. The third lens group includes a third lens, a forth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens.